html, body {
    height: 100%;
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f0f2f5;
  }
  
  .page-wrapper {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
  }
  
  .Catalog {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 40px 20px;
  }
  
  .Catalog form {
    width: 100%;
    max-width: 500px;
    background: #ffffff;
    padding: 40px 30px;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    transition: box-shadow 0.3s ease;
  }
  
  .Catalog form:hover {
    box-shadow: 0 6px 25px rgba(0, 0, 0, 0.12);
  }
  
  .Catalog p {
    margin: 20px 0;
    display: flex;
    align-items: center;
    font-size: 16px;
    color: #333;
  }
  
  .Catalog i {
    margin-right: 10px;
  }
  
  .Catalog input[type="text"],
  .Catalog input[type="password"] {
    flex: 1;
    border: none;
    border-bottom: 2px solid #ccc;
    background-color: transparent;
    padding: 10px 12px;
    font-size: 16px;
    color: #333;
    outline: none;
    transition: border-color 0.3s ease, background-color 0.3s ease;
    border-radius: 4px;
  }
  
  .Catalog input[type="text"]:focus,
  .Catalog input[type="password"]:focus {
    border-bottom: 2px solid #00dbde;
    background-color: #f9f9f9;
  }
  .Catalog input[type="submit"] {
    display: block;              /* 让它变成块级元素，才能使用 margin auto */
    margin: 25px auto 0 auto;    /* 顶部 25px，左右 auto 实现居中 */
    width: 150px;                /* 可设置固定宽度或保留 100% */
    padding: 12px;
    font-size: 18px;
    color: #333;
    border: none;
    border-radius: 30px;
    cursor: pointer;
    background-color: #F9EFD6;
    transition: background-color 0.3s ease, transform 0.2s ease;
    text-align: center;
  }
  
  
  .Catalog input[type="submit"]:hover {
    background-color: #f9efd6; 
  }
  
  .Catalog img {
    width: 24px;
    height: 24px;
  }
  
  .code {
    display: flex;
    justify-content: center;
    margin-top: 20px;
  }
  
  .code img {
    width: 120px;
    height: 45px;
    border: 1px solid #ddd;
    border-radius: 6px;
    cursor: pointer;
    transition: box-shadow 0.3s ease;
  }
  
  .code img:hover {
    box-shadow: 0 0 5px rgba(0, 0, 0, 0.1);
  }
  
  .usernameMsg {
    display: none;
  }
  
  .okTips {
    color: green;
    font-size: 14px;
    margin-left: 10px;
  }
  
  .errorTips {
    color: red;
    font-size: 14px;
    margin-left: 10px;
  }
  
  .whole {
    margin-top: 20px;
  }
  
  .btnImg {
    width: 20px;
    height: 20px;
    cursor: pointer;
    transition: transform 0.3s ease;
  }
  
  .btnImg:hover {
    transform: rotate(180deg);
  }
  
  .Information {
    margin-top: 15px;
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
  }
  
  .Information input {
    flex: 1 1 48%;
    border: 1px solid #ddd;
    padding: 10px;
    font-size: 14px;
    border-radius: 6px;
    transition: border-color 0.3s ease;
  }
  
  .Information input:focus {
    border-color: #00dbde;
  }
  